With the discovery during recent years that pistachios can be grown commercially in the San Joaquin Valley of California, substantial acreages of this delicious nut were promptly planted. Such plantings are now coming into production. However, it has now been discovered that without the cheap labor of the foreign countries growing pistachios, it is not economically feasible to hull the harvested pistachios by hand. Further, insofar as can be determined, there has never previously been a practical mechanical huller for pistachios. Thus, after nurturing for many years hundreds of acres of delicate pistachio trees to the point of production, the entire domestic production of pistachios is threatened with collapse before it reaches full production because of the expense of processing pistachios for market.
Further, the hulling of pistachios presents unusual problems of difficult solution. The pericarp of pistachios is stronger, more tenaciously adherent to the shells, and more difficult to remove than the pericarps of many nuts. If the pericarp is not promptly removed from pistachios after harvest, it discolors the shells requiring that the normally attractive straw colored shells be colored to hide undesirable stains. For this reason, most commercial pistachios are dyed an unnatural and undesirable pink or red color to obscure the stains. Even with abundant hand labor available to foreign producers, it is usually not feasible to hull sufficiently large volumes of pistachios soon enough after harvest to avoid shell discoloration.